This invention relates to an improved liquid-gas condensation tower and particularly relates to a recycle gas scrubbing tower useful in a gas phase olefin polymerization system.
A conventional recycle gas scrubber used in a gas phase olefin polymerization system such as used in U.S. Pat. No. 3,971,768, incorporated herein by reference, comprises a condensation tower designed to separate quench liquid, monomer, hydrogen and polymer fines. A typical tower comprises a vertical cylindrical chamber in which unseparated off-gas material from a gas-phase olefin polymerization reactor is introduced, and condensor trays positioned at various heights along the chamber. Gaseous material is removed from the upper portion of the tower while residual liquid material, including polymer fines, is removed from the bottom of the tower. It has been observed that in using a conventional scrubber apparatus in a gas phase olefin polymerization system, lumps of polymer formed in the condensation tower and caused fouling and pluggage in downstream equipment. An improved scrubber apparatus which avoids formation of polymer lumps would prevent many unplanned unit shutdowns.